When electron beams (cathode rays) emitted for sterilizing cellular microorganisms collide with metallic shields (containing lead) disposed as shields, the electron beams are attenuated and then are reflected and diffracted as X-rays in a widely diffused state. For example, if electron beams collide with the shield three or four times, although depending on the intensity thereof, X-rays can be attenuated to a degree of intensity that does not affect a human body.
For example, if an electron beam irradiation nozzle is inserted into the inlet of a container to sterilize the inner surface of the container, electron beams are emitted from the entire periphery of the electron beam irradiation nozzle. If a revolving transport device that is a rotary device stored in a shield chamber is used to continuously sterilize the container at a high speed, the container is sterilized with the electron beam irradiation nozzle inserted into the inlet, the electron beam irradiation nozzle being revolved with the container. In this case, an electron beam generator cannot turn on or off electron radiation because a high voltage is supplied, leading to continuous radiation. Thus, electron beams (X-rays) leaking from the entrance or exit of the container formed on the shield chamber may be seriously shielded or attenuated.
For example, patent literature 1 is proposed as a technique of sterilizing the inner surface of a container with an electron beam irradiation nozzle inserted into the inlet of the container. Patent literature 2 proposes the layout of an electron beam irradiation nozzle for sterilizing an inner surface and an electron beam irradiator for sterilizing an outer surface.